Keyboard of calculating machines



Nov. 4, 1941. R. HOFGAARD v 2,261,115

I KEYBOARD OF CALCULATING MACHINES l Filed April 21, 1938 f/P y g Patented Ney. 4, 1941 KEYBoann oF CALCULATING MACHINES Rolf Hotgaard, Sondre Hellerud Gaard, Nordstrandshogda pr Oslo, Norway Application April 21, 1938, Serial No. 203,458 In Norway April 22, 1937 (ci. zas-145) 2 Claims.

for all numerals, i. e. in due order for units, tens,

hundreds, and so forth. This latter system is employed, for instance, in the so-called ten-key machines.

According to this invention, only certain of the basic numbers of the numerical system are represented by individual keys and the other basic numbers are represented by different combinations of a plurality of the keys, and the relative arrangement of the several keys is such that will always be possible by one finger only to actuate the individual'keys or combinations of keys to obtain all basic numbers of the system.

A suitable embodiment of the invention is illustrated in the accompanying drawing. shows a set of four keys viewed from above. Fig. 2 shows the same set of keys viewed from the side. and Fig. 3 is a rear view thereof. Figs. 4, 5 and 6 show thekey for the numeral 1 viewed from above, from the front, and from the side, respectively.

According to the embodiment shown, there are only four keys i, 2, 3 and 4, which primarily represent the numerals 1, "8, "2" and "4" and then also the numerals 3, 5, 6, 7 and 9. These numerals are arranged on the keys in a manner such that when a certain numeral is pressed upon, a single key or a plurality of keys will be actuated at the same time, with the result that a single key device or a plurality of such devices are brought into functioning, according to the numerical value of the combination of keys.

Each one of the four main keys I, 2, 3 and t is provided with a pin 5, which is mounted within a sleeve 6, said sleeves being rigidly connected `with a key board plate 1. The pin 5 extends through the plate 'i and is provided at its lower end with a nger 8 for the actuation. of a set of contact springs S, for example.- Obviously, the pins-5 may also be arranged to actuate such mechanical key devices as are provided in the conventional calculating machines.

Immediately beneath the plate l, a spring- Fig. 1'

loaded locking plate I0 is arranged for the keys, in a manner such that said locking plate may slidel to and fro, while being guided by means of connecting screws (not shown), the pins projecting through oval slots in the plate. The keys may be automatically locked with the aid of conical restrictions II on the key pins 5, after the latter have been pressedr down and the plate I0 has been displaced by means of its spring, so that this plate with the said oval recess is pressed into the restriction II of the pin 5.

In the embodiment shown, the front keys I and 2 representing the numerals "1 and "8 are arranged on a lower level than the two rear keys 3 and 4 representing .the numerals 2 The key lis connected to a cross piece I2 which is located between the keys I, 3 and 2, 4, respectively, and the upper surface of which is on a level with the rear keys 3 and 4. Hereby it will be possible to obtain different numerical combinations. The numeral 3 is arranged in part on the cross piece l2 (numeral 1) and partly on the key 3 (numeral 2") The numeral rl5 is, arranged partly on the cross piece I2 and partly on the key 4 (numeral 4). The numeral "7 is arranged partly on the cross piece I2, partly on the key 3, and partly on the key 4. The numeral 6 is arranged partly on the key 3 and partly on the key 4, and the numeral "9 is arranged partly on the key I and partly on the key,2 (compare Fig. 1). By pressing with the finger upon that numeral l to 9 that is to be entered, one or more of the keys will be depressed to close one or more of the contacts 9 that correspond to the values 4, 8, l and 2, respectively, as viewed from the left in Fig. 3.

The stepped arrangement of the keys precludes a false entry of a value in excess of 9. The lower ievel keys l and It will bedepressed simultaneously when the operator places his finger on the marking 9 at the adjacent edge portions of these keys, and either or-both of the keys 3 and l may be operated with key I by placing the finger on one of the markings 3, "5 or "7 at the adjacent portions of keys 3, 4 and of the extension I2 of the key i. Since the finger tip must be placed on the lower level key 2 to enter the value 8, the right hand portion of the extension I2 ci key I acts as a bar or shield to p revent the simultaneous depression of key 2, and lthe keys 3 or 4. it is possible, of course, to depress any combination of two or more keys when two fingers are used but the practice is to use only one finger in actuating the keys.

What I claim is:

l. A keyboard structure `for use in calculating machines and the like comprising a set of keys having four striking surface portions grouped closely and havingindividual contact-closing extensions corresponding in number with said striking portions, and a plurality of markings upon said surface portions to represent numerals in excess of the number of surface portions, there being a numeral individual to each surface portion and, in addition, several numerals that are disposed in part upon one surface portion and in part upon another, the striking surface portions 

